/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ParentLocationPath.java,v 1.2.4.1 2005/09/12 10:56:30 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ALOAD;
import com.sun.org.apache.bcel.internal.generic.ASTORE;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
import com.sun.org.apache.bcel.internal.generic.NEW;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
import com.sun.org.apache.xml.internal.dtm.Axis;
import com.sun.org.apache.xml.internal.dtm.DTM;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
final class ParentLocationPath extends RelativeLocationPath {

  private Expression _step;
  private final RelativeLocationPath _path;
  private Type stype;
  private boolean _orderNodes = false;
  private boolean _axisMismatch = false;

  public ParentLocationPath(RelativeLocationPath path, Expression step) {
    _path = path;
    _step = step;
    _path.setParent(this);
    _step.setParent(this);

    if (_step instanceof Step) {
      _axisMismatch = checkAxisMismatch();
    }
  }

  public void setAxis(int axis) {
    _path.setAxis(axis);
  }

  public int getAxis() {
    return _path.getAxis();
  }

  public RelativeLocationPath getPath() {
    return (_path);
  }

  public Expression getStep() {
    return (_step);
  }

  public void setParser(Parser parser) {
    super.setParser(parser);
    _step.setParser(parser);
    _path.setParser(parser);
  }

  public String toString() {
    return "ParentLocationPath(" + _path + ", " + _step + ')';
  }

  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    stype = _step.typeCheck(stable);
    _path.typeCheck(stable);

    if (_axisMismatch) {
      enableNodeOrdering();
    }

    return _type = Type.NodeSet;
  }

  public void enableNodeOrdering() {
    SyntaxTreeNode parent = getParent();
    if (parent instanceof ParentLocationPath) {
      ((ParentLocationPath) parent).enableNodeOrdering();
    } else {
      _orderNodes = true;
    }
  }

  /**
   * This method is used to determine if this parent location path is a
   * combination of two step's with axes that will create duplicate or
   * unordered nodes.
   */
  public boolean checkAxisMismatch() {

    int left = _path.getAxis();
    int right = ((Step) _step).getAxis();

    if (((left == Axis.ANCESTOR) || (left == Axis.ANCESTORORSELF)) &&
        ((right == Axis.CHILD) ||
            (right == Axis.DESCENDANT) ||
            (right == Axis.DESCENDANTORSELF) ||
            (right == Axis.PARENT) ||
            (right == Axis.PRECEDING) ||
            (right == Axis.PRECEDINGSIBLING))) {
      return true;
    }

    if ((left == Axis.CHILD) &&
        (right == Axis.ANCESTOR) ||
        (right == Axis.ANCESTORORSELF) ||
        (right == Axis.PARENT) ||
        (right == Axis.PRECEDING)) {
      return true;
    }

    if ((left == Axis.DESCENDANT) || (left == Axis.DESCENDANTORSELF)) {
      return true;
    }

    if (((left == Axis.FOLLOWING) || (left == Axis.FOLLOWINGSIBLING)) &&
        ((right == Axis.FOLLOWING) ||
            (right == Axis.PARENT) ||
            (right == Axis.PRECEDING) ||
            (right == Axis.PRECEDINGSIBLING))) {
      return true;
    }

    if (((left == Axis.PRECEDING) || (left == Axis.PRECEDINGSIBLING)) &&
        ((right == Axis.DESCENDANT) ||
            (right == Axis.DESCENDANTORSELF) ||
            (right == Axis.FOLLOWING) ||
            (right == Axis.FOLLOWINGSIBLING) ||
            (right == Axis.PARENT) ||
            (right == Axis.PRECEDING) ||
            (right == Axis.PRECEDINGSIBLING))) {
      return true;
    }

    if ((right == Axis.FOLLOWING) && (left == Axis.CHILD)) {
      // Special case for '@*/following::*' expressions. The resulting
      // iterator is initialised with the parent's first child, and this
      // can cause duplicates in the output if the parent has more than
      // one attribute that matches the left step.
      if (_path instanceof Step) {
        int type = ((Step) _path).getNodeType();
        if (type == DTM.ATTRIBUTE_NODE) {
          return true;
        }
      }
    }

    return false;
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

    // Compile path iterator
    _path.translate(classGen, methodGen); // iterator on stack....

    translateStep(classGen, methodGen);
  }

  public void translateStep(ClassGenerator classGen, MethodGenerator methodGen) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    // Backwards branches are prohibited if an uninitialized object is
    // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed.
    // We don't know whether this code might contain backwards branches
    // so we mustn't create the new object until after we've created
    // the suspect arguments to its constructor.  Instead we calculate
    // the values of the arguments to the constructor first, store them
    // in temporary variables, create the object and reload the
    // arguments from the temporaries to avoid the problem.

    LocalVariableGen pathTemp
        = methodGen.addLocalVariable("parent_location_path_tmp1",
        Util.getJCRefType(NODE_ITERATOR_SIG),
        null, null);
    pathTemp.setStart(il.append(new ASTORE(pathTemp.getIndex())));

    _step.translate(classGen, methodGen);
    LocalVariableGen stepTemp
        = methodGen.addLocalVariable("parent_location_path_tmp2",
        Util.getJCRefType(NODE_ITERATOR_SIG),
        null, null);
    stepTemp.setStart(il.append(new ASTORE(stepTemp.getIndex())));

    // Create new StepIterator
    final int initSI = cpg.addMethodref(STEP_ITERATOR_CLASS,
        "<init>",
        "("
            + NODE_ITERATOR_SIG
            + NODE_ITERATOR_SIG
            + ")V");
    il.append(new NEW(cpg.addClass(STEP_ITERATOR_CLASS)));
    il.append(DUP);

    pathTemp.setEnd(il.append(new ALOAD(pathTemp.getIndex())));
    stepTemp.setEnd(il.append(new ALOAD(stepTemp.getIndex())));

    // Initialize StepIterator with iterators from the stack
    il.append(new INVOKESPECIAL(initSI));

    // This is a special case for the //* path with or without predicates
    Expression stp = _step;
    if (stp instanceof ParentLocationPath) {
      stp = ((ParentLocationPath) stp).getStep();
    }

    if ((_path instanceof Step) && (stp instanceof Step)) {
      final int path = ((Step) _path).getAxis();
      final int step = ((Step) stp).getAxis();
      if ((path == Axis.DESCENDANTORSELF && step == Axis.CHILD) ||
          (path == Axis.PRECEDING && step == Axis.PARENT)) {
        final int incl = cpg.addMethodref(NODE_ITERATOR_BASE,
            "includeSelf",
            "()" + NODE_ITERATOR_SIG);
        il.append(new INVOKEVIRTUAL(incl));
      }
    }

        /*
         * If this pattern contains a sequence of descendant iterators we
         * run the risk of returning the same node several times. We put
         * a new iterator on top of the existing one to assure node order
         * and prevent returning a single node multiple times.
         */
    if (_orderNodes) {
      final int order = cpg.addInterfaceMethodref(DOM_INTF,
          ORDER_ITERATOR,
          ORDER_ITERATOR_SIG);
      il.append(methodGen.loadDOM());
      il.append(SWAP);
      il.append(methodGen.loadContextNode());
      il.append(new INVOKEINTERFACE(order, 3));
    }
  }
}
